The Effect of Psychological Distress and Personality Traits on Cognitive Performances and the Risk of Dementia in Patients with Mild Cognitive Impairment

Background: The relation between psychological distress, personality traits, and cognitive decline in cognitively impaired patients remains unclear. Objective: To investigate the effect of psychological distress and personality traits on cognitive functioning in subjects with mild cognitive impairment (MCI); and to investigate the predictive accuracy of these factors for the development of dementia. Methods: MCI patients (n = 343, age: 60.9 +/- 9.9 years, 38% female, and MMSE score: 28.1 +/- 1.9) were included from the Maastricht memory clinic. All patients underwent a standardized neuropsychological assessment (including tests for measuring mental speed (Trail Making Test (TMT) part A and Stroop Color Word Test (SCWT) part I), executive functioning (TMT part B and SCWT part III), memory (15-Word Learning Tests), and verbal fluency (1-minute animals)), CT or MRI, and blood assessment. The Dutch Personality Questionnaire (DPQ) and the 90-items Symptom Check List (SCL-90) were used to measure personality traits and psychological distress. Conversion to dementia was assessed two, five, and ten years after baseline. The mean follow-up period was 6.7 +/- 3.4 years. Results: The Psychoneuroticism score of the SCL-90 was associated with slower performances on SCWT part I and TMT part A. The subdomain Neuroticism of the DPQ was also associated with slower scores on the TMT part A. At follow-up, 85 (25.9%) subjects had developed dementia. The SCL-90 total score, and the subscales, Anxiety, Somatization, Insufficiency in thought and action, and Sleeping problems were associated with a decreased risk for developing (AD-type) dementia. Conclusion: Psychological distress negatively affected information processing speed, but was not associated with an increased risk of developing dementia in patients with MCI.